Validation of a neurovascular comorbidities index for retrospective database analysis

OBJECTIVE: Comorbidities have a significant effect on patient outcomes. Accounting for this effect is especially important in retrospective reviews of large databases; overpowered studies are at risk for finding significant results because of inaccurate patient risk stratification. The authors previously created a neurovascular comorbidities index (NCI) for patients with an unruptured intracranial aneurysm and found that the model's ability to predict patient outcomes was statistically significantly improved over that of the routinely used Charlson Comorbidity Index (CCI) and Elixhauser Comorbidity Index (ECI). In this study, the authors aimed to validate use of the NCI over that of the CCI and ECI for risk stratification of patients with other neurovascular diseases. METHODS: The authors queried the National (Nationwide) Inpatient Sample database for the years 2002-2012 to compare the accuracy of the previously validated NCI with that of the CCI and ECI with respect to predicting outcomes for patients who had an arteriovenous malformation, a ruptured intracranial aneurysm, carotid artery stenosis, or dural arteriovenous fistula and who underwent surgical intervention. RESULTS: For patients with an arteriovenous malformation, the NCI outperformed the CCI and ECI in predicting poor outcome, hospital length of stay (LOS), and total cost but was equivalent to the CCI in predicting death. For patients with a ruptured intracranial aneurysm, the NCI outperformed the ECI and CCI in predicting death, poor outcome, LOS, and total cost. For patients with carotid artery stenosis, the NCI outperformed the ECI and CCI in predicting LOS, but it was equivalent to the ECI in predicting death and total cost and inferior to the CCI in predicting poor outcome (p < 0.002 for all). An insufficient number of patients with dural arteriovenous fistula who underwent surgical intervention were available for analysis (n < 10), and they therefore were excluded from study. For 11 of 12 metrics, the NCI was the significantly more efficient model. CONCLUSIONS: The NCI outperforms the CCI and ECI by providing more appropriate and efficient risk stratification of patients regarding death, outcome, LOS, and cost. Given this finding, the NCI should be used for retrospective reviews of patient outcomes instead of the CCI or ECI.

Size and location of ruptured intracranial aneurysms: consecutive series of 1993 hospital-admitted patients

OBJECTIVE Large consecutive series on the size and location of ruptured intracranial aneurysms (RIAs) are limited, and therefore it has been difficult to estimate population-wide effects of size-based treatment strategies of unruptured intracranial aneurysms. The authors' aim was to define the size and location of RIAs in patients diagnosed with subarachnoid hemorrhage due to aneurysm rupture in a high-volume academic center. METHODS Consecutive patients admitted to a large nonprofit academic hospital with saccular RIAs between 1995 and 2009 were identified, and the size, location, and multiplicity of RIAs were defined and reported by patient sex. RESULTS In the study cohort of 1993 patients (61% women) with saccular RIAs, the 4 most common locations of RIAs were the middle cerebral (32%), anterior communicating (32%), posterior communicating (14%), and pericallosal arteries (5%). However, proportional distribution of RIAs varied considerably by sex; for example, RIAs of the anterior communicating artery were more frequently found in men than in women. Anterior circulation RIAs accounted for 90% of all RIAs, and 30% of the patients had multiple intracranial aneurysms. The median size (measured as maximum diameter) of all RIAs was 7 mm (range 1-43 mm), but the size varied considerably by location. For example, RIAs of the ophthalmic artery had a median size of 11 mm, whereas the median size of RIAs of the pericallosal artery was 6 mm. Of all RIAs, 68% were smaller than 10 mm in maximum diameter. CONCLUSIONS In this large consecutive series of RIAs, 83% of all RIAs were found in 4 anterior circulation locations. The majority of RIAs were small, but the size and location varied considerably by sex. The presented data may be of help in defining effective prevention strategies.